Question

H_E_L_P_!

Your test scores in science are 83 and 87. What possible scores can you earn on your next test to have a test average between 85 and 90, inclusive?

Answer 1

@DanJS

Answer 2

83 + 87 + x all divided by 3

Answer 3

equals

Answer 4

85

Answer 5

that is the lowest

Answer 6

For the lowest score
\[\frac{ 83 + 8 7 + x }{ 3 } = 85\]

Answer 7

Ok what does inclusive mean ?

Answer 8

multiply both sides by 3

83 + 87 + x = 255

take off 83 and 87 from both sides

x = 255 - 83 - 87 = 85

To get an average of 85, you need at least an 85 on the next test

Answer 9

Do the same for the higher average

solve

(83 + 87 + x)/3 = 90

Answer 10

inclusive means, including 85 and 90

\[85 \le \frac{ 83 + 87 + x }{ 3 }\le 90\]

the equals part in the less than or equal to

Answer 11

oh Gotcha

Answer 12

(83 + 87 + x)/3 = 90

solve that for the upper bound